1. Field of the Invention
The invention relates to an electric wire with terminal and a method of manufacturing the same, in particular, to an electric wire with terminal which is wired inside a device of a vehicle, etc., and has a conductor having a large cross-sectional area, and to a method of manufacturing the same.
2. Description of the Related Art
A wire with terminal in which a terminal for equipment connection is preliminarily bonded to and integrated with a wire conductor is often used for wiring inside a device of a vehicle, etc.
As a method of connecting a terminal to a wire conductor, a method in which a wire conductor having a certain volume (cross-sectional area) is compression-bonded to a surface of a plate-like terminal formed of Cu or a Cu alloy by using a compression device or a compression tool, so-called “compression joint method”, is generally employed in a method of manufacturing a wire with terminal.
On the other hand, when it is not possible to apply much compressing force due to a material, etc., of a conductor, an ultrasonic bonding method in which a terminal and a conductor are bonded by applying ultrasonic energy and pressure to a connection interface therebetween is sometimes employed. The ultrasonic bonding method is sometimes called an ultrasonic welding process.
The ultrasonic bonding method is advantageous in that it is easy to obtain reliability of electrical connection since an active surface can be exposed by destroying an oxide film each formed on the surfaces of the terminal and the conductor using ultrasonic.
JP-A 2003-117666, which is a prior art, describes an ultrasonic compression bonding apparatus which allows continuous conduction of ultrasonic bonding and compression joint in one apparatus. According to JP-A 2003-117666, the ultrasonic compression bonding apparatus compensates for deficiency of the mechanical connection strength in the ultrasonic bonding by combining the compression joint and it is thereby possible to ensure mechanical connection strength between a terminal and a conductor and to obtain reliability of electrical connection without applying excessive ultrasonic energy or pressure during the ultrasonic bonding. In addition, according to JP-A 2003-117666, the ultrasonic compression bonding apparatus allows efficient connection work by continuously conducting the ultrasonic bonding and the compression joint.
Meanwhile, JP-A 7-326412 describes a plate like terminal which has a connecting portion connected to an electrical equipment and a pressure bonding portion connected to a wire, and in which at least two or more pressure bonding portions connected to a wire are alternately provided in a vertical direction with respect to a flat surface of the connecting portion, i.e., in an opposing direction, and notched terminal pieces composing the pressure bonding portions and used for pressure bonding are each shaped into a cylindrical closed barrel shape by using the compression joint method.